The prime minister last night made a last-ditch plea to rebel backbenchers to support his controversial education bill after claiming that the proposals were "the crux" of his government's reforming agenda.

On the eve of the publication of the bill, Tony Blair said his proposals for reforming the state education system in England were "extremely important to the future of a Labour government". His message to the 100-plus backbenchers threatening to vote against the reforms was that the current package - already diluted by concessions earlier this month - is now non-negotiable.

At a Downing Street seminar, Mr Blair insisted private firms, universities and local authorities all had a role in education and that the reforms would allow these partnerships to flourish. The white paper proposes a new breed of independent trust schools freed from local authority control to run their own affairs with the backing of business groups, parents' bodies and faith organisations.

Downing Street paraded local authority leaders to publicly express their support for the proposals.

Flanked by the education secretary, Ruth Kelly, who was in meetings with Labour backbenchers and opposition MPs yesterday, Mr Blair insisted the furore over the proposals would be forgotten once they were in place. He was speaking before he addressed concerns about the proposals at a regular meeting of the parliamentary Labour party.

He said it was time to build on the "massive" investment ministers had made in public services and raise standards throughout the system, because state education in England was still not good enough. "It's what you want for your own children ... that is why it's important to get this through - it's far more important than the process," he said.

Mr Blair said change was always difficult but that critics seized on the most "ludicrous and far-fetched examples" of reform - for example "what happens when a gang of crooks comes in and wants to run a school" - and asked whether the government would allow it.

"While there remain significant numbers of young people not getting the education they need ... we have got to continue with change. Change in order to help children - particularly those from the most disadvantaged backgrounds, but not only those children - to do better and fulfil their potential," he said.

Today's bill will be published alongside Ms Kelly's full response to the Commons select committee, following a holding letter to its chairman, Barry Sheerman, earlier this month in which she agreed to concessions, including banning all interviewing for admissions.

No 10 says the concessions do not dilute the reforms, but critics say ministers will have been licking their wounds.

In the letter Ms Kelly said the government had decided schools must act in accordance with the code on admissions debarring selection, and not merely take note of it. The code will not be written into the primary legislation because it is deemed unworkable.

The local admissions forum, a blend of all local schools and the local authority, will also be given a new power to object to the school adjudicator if it believes a local school is not following the code, or not having regard to local needs.

Ministers have also agreed to allow local authorities to retain their power to set up new community schools, which was due to be scrapped under the original white paper. But many MPs want the government to remove the requirement for the education secretary to give her approval for any new community schools. Ms Kelly said yesterday she planned to retain this veto.

Last night a spokesman for the Department for Education and Skills said: "The bill will not contain any new surprises or additional clarifications. The policy is now set."

The Liberal Democrat education spokesman, Ed Davey, said: "In the prime minister's rush to find a legacy, key principles are being lost. Labour are sacrificing equality of opportunity, accountability to parents and the community ... Tony Blair is right our schools need reform, but not the type he is suggesting. If he wants to be truly radical he should be addressing the outdated curriculum, lack of expert teachers and giving real choice to pupils to engage them in learning."